SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance. Clarifications Students will use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance. Students will identify, analyze, and/or predict inheritance patterns caused by various modes of inheritance. Content Limits Items referring to general dominant and recessive traits may address but will not assess the P and generations. F1 Items addressing dihybrid crosses or patterns that include codominance, incomplete dominance, multiple alleles, sex-linkage, or polygenic inheritance may assess the P and generations. F1 Stimulus Attributes Inheritance outcomes may be expressed in percent, ratios, or fractions. Scenarios may refer to codominance or incomplete dominance but not both codominance and incomplete dominance. Punnett squares may be used to predict outcomes of a cross. Response Attribute Options may include codominance or incomplete dominance but not both. ESSENTIAL QUESTION: How do genes influence the variety of organisms that exist?

Mendelian Genetics

Gregor Mendel: Considered the “Father of Genetics” Genetics – the study of heredity and the variation of inherited traits. **Inheritance theory – states genetic material of offspring is a uniform blend of the parents’ genetic material.

Key Vocabulary for Understanding Genetics Gene: small section of DNA passed from parents to offspring that codes for a particular specific trait.

Key Vocabulary for Genetics Alleles- All the different forms of the same gene. Types of Alleles: Dominant allele - Prevents the expression of another allele when in a heterozygote, represented by capital letter. Recessive allele - expression is masked/hidden in a heterozygote, represented by a lower case letter.

Key Vocabulary for Genetics Genotype: combination of genes that are inherited from both parents. Homozygous dominant two dominant alleles- TT Homozygous recessive Two recessive alleles- tt Heterozygous/Hybrid One dominant and one recessive- Tt Remind students that prefixes give clues to the meaning of the words. “Homo” means same. “Hetero” means different.

Phenotype: physical appearance caused by the genotype TT Tt tt Phenotype Tall stems Short stems

Law of Segregation: T t T t TT The two alleles for a trait separate during meiosis when gametes (eggs and sperm) are formed. A parent passes on only one allele for each trait to each offspring. tt t Please clarify that this occurs for homologous chromosomes. Also, clarify that the gametes and offspring represent one of several possibilities. Tt t T from Mom from Dad offspring Dad Mom

Law of Independent Assortment Two or more genes on separate chromosomes are inherited independently of each other. Example: Seed color and flower color are inherited separately. Limit discussion to the basics shown; do not introduce the concept of linkage in this FCIM lesson.

GENETICS AND PREDICTIONS Scientists use probability to predict traits in offspring. A Punnett Square organizes information to make genetic predictions. Monohybrid Cross (one trait) & Complete Dominance

Completing a Punnett Square Step 1: Determine each parents gametes and all possible gamete allele combinations. Step 2: Complete the Punnett square Step 3: Analyze genotypic and phenotypic ratios.

Complete Dominance Monohybrid Inheritance of one trait from each parent. T t T t Parents are both heterozygous tall pea plants. P1 ______ X ______ T t Offspring Genotype 1 T T : 2 T t : 1 t t T T T T t Offspring Phenotype t T t t t 3 Tall : 1 Short

Scaffolding Skills Dominant Allele D e K L N o R S Recessive Allele M n d F G I k P Homozygous (Pure) Dominant Genotype AA Gg KK ll pp Rr TT Homozygous (Pure) Recessive Genotype Ee Ff HH Oo qq Uu ww Dominant Phenotype AA Dd EE ff Jj RR Ss Recessive Phenotype Aa Gg Ff Oo PP ss tt Heterozygous Dominant Genotype RR Mm cc TT Hh ee Ff

Trait Genotype Phenotype Heterozygous stem length   Homozygous dominant seed shape Heterozygous colored seed coat Homozygous recessive stem length Heterozygous for both pod color and shape. Homozygous recessive flower position and Heterozygous for stem length Homozygous dominant for both seed shape and color. Homozygous dominant for seed shape and Homozygous recessive for pod color. Ll Long Stem RR Round Cc Colored ll Short stem Green & Smooth GgSs aaLl Terminal & Long RRYY Round & Yellow RRGG Round & Green